feat: adding forum thread notification (#337)

* feat: adding gsi univid by threadid for table threads for thread notification

* feat: adding lambda for notification

* feat: creating lambda functions and rest api

* fix: fixing Univ Id to univ id

lib/constructs/business/rest-api-service.ts

@@ -718,6 +718,7 @@ export class ForumThreadsApiService extends RestApiService {
     const threadResource = boardResource.addResource('{thread_id}');
     const userResource = root.addResource('user');
     const testResource = root.addResource('test');
+    const notificationResource = root.addResource('notify');
 
     const optionsForumHome = root.addCorsPreflight({
       allowOrigins: allowOrigins,
@@ -779,6 +780,12 @@ export class ForumThreadsApiService extends RestApiService {
       ],
     });
 
+    const optionsNotifyThreads = notificationResource.addCorsPreflight({
+      allowOrigins: allowOrigins,
+      allowHeaders: allowHeaders,
+      allowMethods: [apigw2.HttpMethod.GET],
+    });
+
     const getRespModel = scope.apiEndpoint.addModel('threads-get-resp-model', {
       schema: forumThreadGetRespSchema,
       contentType: 'application/json',
@@ -833,6 +840,10 @@ export class ForumThreadsApiService extends RestApiService {
       forumThreadsFunctions.deleteFunction,
       { proxy: true },
     );
+    const notifyIntegration = new apigw.LambdaIntegration(
+      forumThreadsFunctions.getNotificationFunction,
+      { proxy: true },
+    );
     const testPostIntegration = new apigw.LambdaIntegration(
       forumThreadsFunctions.testPostFunction,
       { proxy: true },
@@ -940,6 +951,20 @@ export class ForumThreadsApiService extends RestApiService {
         requestValidator: props.validator,
       },
     );
+    const notifyForumThreads = notificationResource.addMethod(
+      apigw2.HttpMethod.GET,
+      notifyIntegration,
+      {
+        operationName: 'NotifyThreadCount',
+        methodResponses: [
+          {
+            statusCode: '200',
+            responseParameters: lambdaRespParams,
+          },
+        ],
+        requestValidator: props.validator,
+      },
+    );
     const testPostForumThreads = testResource.addMethod(
       apigw2.HttpMethod.POST,
       testPostIntegration,
@@ -981,6 +1006,10 @@ export class ForumThreadsApiService extends RestApiService {
         [apigw2.HttpMethod.GET]: getUserForumThreads,
         [apigw2.HttpMethod.OPTIONS]: optionsUserThreads,
       },
+      '/forum/notify': {
+        [apigw2.HttpMethod.GET]: notifyForumThreads,
+        [apigw2.HttpMethod.OPTIONS]: optionsNotifyThreads,
+      },
       '/forum/{board_id}': {
         [apigw2.HttpMethod.POST]: postForumThreads,
         [apigw2.HttpMethod.OPTIONS]: optionsForumBoards,

lib/constructs/common/lambda-functions.ts

@@ -491,6 +491,7 @@ export class ForumThreadFunctions extends Construct {
   readonly postFunction: lambda.Function;
   readonly patchFunction: lambda.Function;
   readonly deleteFunction: lambda.Function;
+  readonly getNotificationFunction: lambda.Function;
   readonly testPostFunction: lambda.Function;
   readonly testGetFunction: lambda.Function;
 
@@ -645,6 +646,23 @@ export class ForumThreadFunctions extends Construct {
       environment: props.envVars,
     });
 
+    this.getNotificationFunction = new lambda_py.PythonFunction(
+      this,
+      'notify-thread',
+      {
+        entry: 'src/lambda/get-thread-notify',
+        description:
+          'return forum thread count from given date in the database.',
+        functionName: 'get-thread-notify',
+        logRetention: logs.RetentionDays.ONE_MONTH,
+        memorySize: 128,
+        role: DBReadRole,
+        runtime: lambda.Runtime.PYTHON_3_9,
+        timeout: Duration.seconds(3),
+        environment: props.envVars,
+      },
+    );
+
     this.testPostFunction = new lambda_py.PythonFunction(
       this,
       'test-post-thread',

lib/constructs/persistence/database.ts

@@ -107,6 +107,12 @@ export class DynamoDatabase extends Construct {
       sortKey: { name: 'thread_id', type: dynamodb.AttributeType.STRING },
       projectionType: dynamodb.ProjectionType.ALL,
     });
+    this.tables[Collection.THREAD].addGlobalSecondaryIndex({
+      indexName: 'UnivIDbyThreadIDIndex',
+      partitionKey: { name: 'univ_id', type: dynamodb.AttributeType.NUMBER },
+      sortKey: { name: 'thread_id', type: dynamodb.AttributeType.STRING },
+      projectionType: dynamodb.ProjectionType.ALL,
+    });
 
     // this.tables[Collection.THREAD].addLocalSecondaryIndex({
     //   indexName: 'GroupIndex',

src/lambda/get-thread-notify/index.py

@@ -0,0 +1,34 @@
+from boto3.dynamodb.conditions import Key, Attr
+from utils import JsonPayloadBuilder, table, resp_handler
+
+
+@resp_handler
+def get_thread_notify(last_checked_date):
+
+    univ_id = 1
+
+    lower_bound_thread_id = f"{last_checked_date}_"
+    # Query the GSI
+    response = table.query(
+        IndexName='UnivIDbyThreadIDIndex',
+        KeyConditionExpression=Key('univ_id').eq(univ_id) & Key(
+            'thread_id').gt(lower_bound_thread_id),
+        ScanIndexForward=False  # Sorting by thread_id in descending order
+    )
+
+    count = len(response['Items'])
+
+    body = JsonPayloadBuilder().add_status(True)\
+                               .add_data(count)\
+                               .add_message('').compile()
+
+    return body
+
+
+def handler(event, context):
+
+    params = {
+        "last_checked_date": event['queryStringParameters'].get('lastChecked', '20230912201031')
+    }
+
+    return get_thread_notify(**params)

src/lambda/get-thread-notify/utils.py

@@ -0,0 +1,82 @@
+import boto3
+import json
+import logging
+import os
+from decimal import Decimal
+
+db = boto3.resource("dynamodb", region_name="ap-northeast-1")
+table = db.Table(os.getenv('TABLE_NAME'))
+
+s3_client = boto3.client('s3')
+bucket = os.getenv('BUCKET_NAME')
+
+
+class DecimalEncoder(json.JSONEncoder):
+    def default(self, obj):
+        if isinstance(obj, Decimal):
+            return float(obj)
+        return json.JSONEncoder.default(self, obj)
+
+
+class JsonPayloadBuilder:
+    payload = {}
+
+    def add_status(self, success):
+        self.payload['success'] = success
+        return self
+
+    def add_data(self, data):
+        self.payload['data'] = data
+        return self
+
+    def add_message(self, msg):
+        self.payload['message'] = msg
+        return self
+
+    def compile(self):
+        return json.dumps(self.payload, cls=DecimalEncoder, ensure_ascii=False).encode('utf8')
+
+
+def api_response(code, body):
+    return {
+        "isBase64Encoded": False,
+        "statusCode": code,
+        'headers': {
+            "Access-Control-Allow-Origin": '*',
+            "Content-Type": "application/json",
+            "Referrer-Policy": "origin"
+        },
+        "multiValueHeaders": {"Access-Control-Allow-Methods": ["POST", "OPTIONS", "GET", "PATCH", "DELETE"]},
+        "body": body
+    }
+
+
+def resp_handler(func):
+    def handle(*args, **kwargs):
+        try:
+            resp = func(*args, **kwargs)
+            return api_response(200, resp)
+        except LookupError:
+            resp = JsonPayloadBuilder().add_status(False).add_data(None) \
+                .add_message("Not found").compile()
+            return api_response(404, resp)
+        except Exception as e:
+            logging.error(str(e))
+            resp = JsonPayloadBuilder().add_status(False).add_data(None) \
+                .add_message("Internal error, please contact [email protected].").compile()
+            return api_response(500, resp)
+
+    return handle
+
+
+def generate_url(bucket_name, object_key, expiration=3600):
+    try:
+        response = s3_client.generate_presigned_url('get_object',
+                                                    Params={'Bucket': bucket_name,
+                                                            'Key': object_key},
+                                                    ExpiresIn=expiration)
+    except Exception as e:
+        logging.error(str(e))
+        return None
+
+    return response